1. Field of the Invention
This invention relates in general to standardization of electronic device/rack assemblies and more particularly to the use of a wiring, signal conditioning, and standardized electrical backplane system.
2. Background of the Invention
There are many problems associated with the interfacing of various electronic devices, particularly with the need to frequently reconfigure automatic test equipment.
Automatic test equipment is configured to optimally test a specific suite of units under test. When this suite changes the test station has to be reconfigured to provide the new test capabilities. The changes that continue to occur in the suite of units to be tested, for example, as a result of improvements, demand a corresponding change in the test equipment. Another reason for reconfiguration is that after a passage of time an instrument used in the test station may become obsolete and will have to be replaced by a new instrument.
It is common in instrument construction to mount electronic equipment in drawers or slide units which slide into a suitable equipment rack in spaced parallel relationship. The so-called "drawers" may comprise modular instrument housings which slide into suitable slots in the rack, or supports for printed circuit boards or cards which plug into a card cage or rack. The electronic equipment in the rack must be suitably interconnected, and this can cause problems when changes must be made in an overall system mounted on the rack.
Different equipment manufacturers or distributors of electronic equipment often do not employ a consistent programming format and protocol. There is often little uniformity in the location and distribution of input/output signals of similar electronic equipment produced by different manufacturers. Even when identical programming formats and protocols are used, details of the implementation differ from manufacturer to manufacturer. Therefore, many electronic assemblies that have identical electrical characteristics are not interchangeable without some sort of programming or reconfiguration.
There are also often mechanical differences between electronic equipment supports or drawers designed to slide into an equipment rack. These differences also prevent easy interchangeability. The differences include rather simple items such as connector quantity, location, size and pin allocation. These seemingly trivial problems force conventional rack wiring to undergo extensive rework when a system has to be reconfigured. Expensive, complex, and time consuming reconstruction often beyond the capability of field personnel to implement, must be performed. This rack wiring has been a major impediment to all previous attempts to provide easy reconfigurability in all existing systems.
Therefore, it is desirable to have a rack wiring and signal conditioning system whereby the input/output signals to electronic devices performing a similar function are identical.
It is particularly desirable that one electronic device may be easily and quickly substituted for another electronic device.
It is further desirable that the system allow the electronic devices within a rack to easily interface with one another.
If is further desirable that such a system facilitate communication between racks.
It is also desirable that such a system not detract from the present advantages of rack systems, such as the ease of access to the electronic equipment.